diff --git a/docs/source/index.rst b/docs/source/index.rst
index 9175d4317..28d197605 100644
--- a/docs/source/index.rst
+++ b/docs/source/index.rst
@@ -169,7 +169,7 @@ Required additional tools
 `64tass <https://sourceforge.net/projects/tass64/>`_ - cross assembler. Install this program somewhere on your shell's search path.
 It's easy to compile yourself, but a recent precompiled .exe (only for Windows) can be obtained from
 `the files section <https://sourceforge.net/projects/tass64/files/binaries/>`_ in the official project on sourceforge.
-*You need at least version 1.56 of this assembler.*
+*You need at least version 1.58.0 of this assembler.*
 If you are on a Debian based Linux, there's a "64tass" package in the repositories, which is a bit old, but it seems to work.
 It's possible to use old versions of 64tass, but it is likely that certain things will break.